A large number of medical diagnostic and therapeutic procedures involve the percutaneous introduction of instrumentation into the blood vessel. For example, coronary angioplasty, angiography, atherectomy, stenting, and numerous other procedures often involve accessing the vasculature through placement of a catheter or other device in a patient's femoral artery or other blood vessel. Once the procedure is completed and the catheter or other diagnostic or therapeutic device is removed, bleeding from the resultant vascular puncture must be stopped.
Traditionally, a medical practitioner applies external pressure to the puncture site to stem bleeding until hemostasis occurs (i.e. when the clotting and tissue rebuilding have sealed the puncture). This method, however, presents numerous problems. In some instances, this pressure must be applied for up to an hour or more, during which time the patient is uncomfortably immobilized. In addition, there exists a risk of hematoma since bleeding from the puncture may continue until sufficient clotting occurs, particularly if the patient moves during the clotting process. Furthermore, application of external pressure to stop bleeding may be unsuitable for patients with substantial amounts of subcutaneous adipose tissue since the skin surface may be a considerable distance from the puncture site, thereby rendering external compression less effective.
Another traditional approach to subcutaneous puncture closure comprises having a medical practitioner internally suture the vessel puncture. This method, however, often requires a complex procedure and requires considerable skill by the medical practitioner.
Mechanical occlusion devices have been proposed for sealing, e.g., atrial septal defects, and typically comprise two expandable disks that sealingly compress tissue surrounding the hole. One such device is described in U.S. Pat. No. 5,425,744 to Fagan et al. A significant drawback to the Fagan device is that, when deployed into a vessel, the device may protrude into the blood stream, thereby disturbing blood flow and causing thrombosis in the vessel.
Apparatus and methods also are known in which a plug is introduced into the vessel puncture, to cover the puncture and promote hemostasis. Various types of plugs have been proposed. One example is described in U.S. Pat. No. 5,061,274 to Kensey, comprising a plug made from animal-derived collagen. Such apparatus may be unsuitable for some patients due to an adverse immunological reaction to animal-derived collagen, which could lead to anaphylactic shock.
U.S. Pat. No. 6,159,232 to Nowakowski describes an apparatus substantially disposed outside a patient's body that activates a clotting cascade within blood, and then introduces the treated blood to the wound site to complete clotting and promote hemostasis. Disadvantageously, the apparatus described in that patent comprises a multiplicity of primarily standard, off-the-shelf components that a medical practitioner would have to assemble prior to use. This greatly is complicates the procedure, and increases opportunities for human error and contamination. Furthermore, the apparatus resulting from the assembly of the numerous individual components may be unwieldy to use and expensive.
In view of these drawbacks, it would be desirable to provide apparatus for sealing a puncture tract by forming and extruding an autologous plug within the puncture tract.
It also would be desirable to provide apparatus for sealing a puncture tract that are easy to use, and decrease opportunities for error and contamination.
It further would be desirable to provide apparatus for sealing a puncture tract that facilitate placement of the apparatus relative to a vessel.
It still further would be desirable to provide apparatus for sealing a puncture tract that prevent leakage of blood congealing agents into a vessel during delivery thereof.